Frangible link



' FRANGIBLE LINK Filed Feb. 1. 1929 Movfety `Patented July 28, 1931 UNITED STATES PATENT OFFICE IEAv w. KNIGHT, 0E PROVIDENCE, RHODE ISLAND, AssIGNoE To GENERAL EIEE Y ,EXTINGUISHER COMPANY, F PROVIDENCE, RHODE ISLAND, A CORPORATION OI" DELAWARE ERANGIB'LE LINK AApplication filed February 1, 1929. Serial No. 336,864.

This invention relatesto improvements in i `sel with spherically-shaped ends joined byy 'contracted neck-portions to the body of the vessel. The yseparable members of the link engage the'ends of the vessel and impose upon "the .latter a tensile stress. These peculiarly shaped vessels are somewhat difficult krto make yand it is an object of the vpresent inv vention to pro-videa link in which a rangible `'vessel ot` plaint'simple shape may be used.

lAnother object is to provide separable members `which canbe arranged with respect to each other'and .with thel frangible vessel so that the force imposed on thelatter will be j one of compression rather than tension, al-

beit the separable members themselves are both pulled. by ,the respective ties to whichy .they are connected.

These objects are attained providing l sep/arable members having parts which tend to move toward one another and by inserting i between said parts a trangible vessel of simy ple bulb shape which, until destroyed, keeps y the vparts relatively stationary. Various em- 'Ubodim'ents are shown in the drawings each illustrativeof how the principles of the invention may be applied, but the scope of the v.patent is not 'to lbe limited to these disclosures for it is intended .to cover by suitable expression in the appended claims whatever I yfeatures of patentable novelty exist in the invention asa whole. f

VIn the accompanying drawings, Figures 1 and 2 are elevations, taken at right angles to one another, of a link concation and structed'in 'accordance with the present in- ,vention;A

Figures 7 ,8 and 9 are a plan, Iside view andelevationin sectionon line l9 9 of Fig ure 8, respectively, 'of another modiiication.

Referring particularly to the drawings, they frangible link of Figuresl and 2 has separable members A and B each having an eye C at one end for engagement with force exerting ties (not shown). Near the other ends o f these members and on the side of each opposite to the tie are suitable seats D adapted to receive the drawn-out kends of a frangible vessel E` This vessel is inade preferably of quartz* initially drawn in the Jform of a tube. It is then made into bulbs or vessels of the shape illustrated herein. The tube is fused'at a zone near its end until the end can be drawn away to bring the' walls of the heated zone` together. Theoriginal end is then broken off and the new drawn-in end of the tube is further heated until it entirely closes and thus forms one end of a vessel. The tube is again heated a short distance from this end and again drawn out and broken olf so that another closed end may be made. yThe part of the tube broken olf becomes a vessel having the previously closed end and another similarly shaped end with a small opening through which the vessel is charged with a highly expansible fluid after which this open end is again fused and the opening closed. Upon being heated to a predetermined temperature the internal pressure exerted by the fluid will cause the vessel toy be completely destroyed.

The above described charged vessel E is positioned with its ends resting on the seats D of the separable members A and B and a clamp F is slipped over these members a little beyond the vessel. Preferably this clamp has a fixed pointed, or knife-edge, jaw

F1 which engages one member B and an adjustable jaw F2 for engagement with thekr pull of thev ties and the other ends exerting a compressive force on the vessel. When the latter is destroyed upon its luid charge being heated toa predetermined degree,- the separable members will be pulled away from the clamp F and from each other thus free- Fi'r ing Whatever has been held in restraint by the link.

In Figures 3 and 4 there is shown a separable member A1 formed as a rigid yoke with the inner surfaces alV of its ends (t converging downward. The other Y separable member Bl is .similarly yokeshaped but its arms b are pivoted at p and theother surfaces bl of their ends are disposed so that When placed lWit-hin the end a and spread apart, the

*surf-aces bi vWill-engage the surfaces al and maintain the separable members together. Intermediate the pivot p and the surfaces -bl each arm of the separable member Gr has seats adapted to receive the ends of the frangible vessel E, onev arm havingy a seat The opposite end-a3, '63, of eacharm is drawn Yao D1 on a threaded stem Zto permit the insertion of -the vessel 'and the subsequent spreading-of the armste make holding Acontact With thesurgfacesal. Upon the shattering of the YYvessel the arms?) collapse'and the two member-.s Alzand B lseparate.

vigures aand@ disclose a link having sepl arable members A2 and B2 adapted to be stamped from -sheetmetal 'Each member comprises tvvoarms, t2 and b2 respectively,

. i-oinedtogether at one end 'by a'grommet H.

cup-shaped, and outstanding .beside theV cups t3, -of-one pair of arms are ears a4. In assembling this link the 'cups '3 are Vplaced ,Withinthe-cups c3, and the tvvo pairs of cups Vare spread vapart-to receive-the vessel E there being suitable seats VD2 provided for this purpose. Y Bolts J are inserted through 'holes `in the ears a4 and the cups and seats clamped against the ends of the vessel. `Upondestruction of thelatter., the pull on the yarms. a2, b2

being transmitted to the curved surfaces ofY the cups (13,53, cause the latter toiseparate l'and thus free lthe separable members.

Thejlink disclosedin Figures 7, S and 9A has a separable member A3 With an eye C jatv one -end and anoifset spherically shaped portiona at the other end. This portion l.is

lreceivednin.a spherical `socket b5 of a sep. arable member B3. Extending `away from ropposi-tesides ofI this socketb5 4are `the 'arms y f5.6 .of a yoke which terminates V:in the neck 57.

YThis *has` a threadedfbore toY accommodate the stem lcZ3of va seat 'D3 for one endof the frangible vessel E.. The vessel also rests on afseat D4 which in turnbottoms on-ashoulder in the hollow of the offset ,portion a5.

kV-Vhen the. frangble vessel isdestroyed by.

the action off itsiiuid contents, the portion .a5 slips out ofthe .socket b5V land the separable .membersare set free.

The advantages ofthis typeof link are many..r ,The .frangiblememberis Yentirely freek from the dangers of corrosion Vand by Suitable selection. of metal, theV separable member 7'can alsoV be made substantially free .from this danger.. The characteristics of the frangildevesself'are permanent;- There is-no members.

cold flow, and the link can be depended upon to give Way at a predetermined temperature no matter how long it has been eX- posed to the elements. In the arrangement of parts disclosed in thisv application, the

-frangible vessel is subjected onlyv to a compressive force which it is most capable of Vresisting. 'in accordance With this invention are capable of supporting loads far beyond the limits Beca-use of this, links constructed permittedV With the ordinary fusiblev links and even greater than the loads deemedsafe when a frangible vessel is subjected to tensile forces. And Where as inthe disclosures of Figures 3-9, the'greater part of the pull of Athe ties -is actually carried by the separable members themselves a-nd :only a component of this pull is applied kas a compressive force on the frangib'le vessel, the links can be relied upon with complete safety and Without likelihood of premature failurefeven under most eXtreme loadings.

I claim c Y i. A frangible link comprising, in combination, members vadapted to be 4connected to ties and separably connected to each other, and a Vfrangible vessel arranged, .to Vresist fcompressively the tendency of said members to sepa-rate; said vessel containing eXpansible fluid adapted uponbeing'heated to a prede- .said contact comprising a. frangible vessel arranged .with .respect vto saidl members to resist the tendencyof said surfaces to separate;

said` vessel "beingr charged With expansible fluid adapted upon .being heated to a .predetermined temperature nto destroysaid vessel:

a. ,A [frangible linkf comprising, in combiconnected to a tie having Ya cup-shaped vportion; a second separable member adapted to be connected to a tie havingk an ofsetvfportionadaptedto be received inthecup-shaped ^portion of the first said member; means vmaintaining said odset portion 'Within said cup-shaped portion thereby tocprevent .separation of the said kmembers; said means 'comprising a chargedfrangible vessel adapted to give Way at a predetermined vtemperature a-nd'thereby permit separation ofisaid 5. Aifrangible link comprising, in ...combi- ..nation, a separable member adapted to be Y nation, a member adapted to be connected to a tie having a socket and a yoke extending laterally away from said socket; a second member adapted to be connected to a tie havfng an offset portion adapted to be received in said socket; and means interposed between said offset portion and the yoke maintaining said portion Within the socket and thereby preventing separation of said members; said means comprising a charged frangible vessel adapted to give Way at a predetermined temperature and thereby permit said portion to be Withdrawn from said socket.

Signed at Providence, Rhode Island, this th day of January, 1929.

IRA W. KNIGHT. 

